Paolo Caaaniga's Stay in Berlin

We present part of the correspondence between Paolo Cazzaniga and his teacher, Felice Casorati, when Cazzaniga was in Berlin as a recipient of a scholarship for specialization in mathematics. The letters reveal Cazzaniga's first steps in mathematical research and show Berlin university life as seen by a young man on his first experience abroad, in a historical period in which anti-Semitism was sending its early alarming messages.